1. Field of the Invention
This invention relates to nozzle assemblies for liquid jet-forming surgical instruments, surgical instruments employing the nozzle assemblies, and methods of fabricating such surgical instruments.
2. Description of the Related Art
Traditionally, many surgical procedures for both open surgery and minimally invasive surgery (i.e., endoscopic, laparoscopic, or arthroscopic surgical procedures) have utilized surgical tools such as scalpels, scrapers, blunt dissectors, lasers, electrosurgical devices, etc., which can have poor tissue differentiating capability, which may easily cause inadvertent damage to tissue surrounding a surgical treatment site, and which do not typically provide for an ability to precisely control a depth of cutting and/or tissue ablation with the instrument and/or effectively provide for evacuation from the treatment site of cut/ablated tissue. Many such surgical procedures can entail more extensive trauma to the patient and/or require longer operating procedures, with associated problems of long recovery periods and potential complication, than is desirable.
Instruments that employ liquid jets have also been utilized in surgical procedures for cutting and ablating tissue. Such instruments can have certain advantages over the above-mentioned traditional surgical instruments for performing surgical and medical procedures. For example, the cutting or ablating power of the liquid jet may be adjusted or controlled by an operator of the instrument, for example by varying the pressure of the liquid supplied to form the jet, to allow for improved tissue differentiation and to reduce inadvertent damage to surrounding tissues when cutting or ablating the target tissue. When operated at lower liquid pressures, the instruments can be utilized for lavage and/or debridement of tissue, without substantial cutting. A variety of such liquid jet surgical instruments for performing open surgical procedures, minimally invasive surgical procedures, and surgical procedures performed on an external portion of the body of a patient (e.g., wound cleansing or skin debridement) are known in the art. Several such instruments are described in commonly-owned U.S. Pat. No. 5,944,686, issued Aug. 31, 1999, U.S. Pat. No. 6,375,635, issued Apr. 23, 2002, and U.S. Pat. No. 6,511,493, issued Sep. 17, 2002, each incorporated herein by reference, and in commonly-owned published U.S. Patent Publication No. 2003/0125660 A1, published Jul. 3, 2003, which is incorporated herein by reference.
Typically, many of the above-described surgical instruments are designed an supplied to be disposable after a single use. As described in the above-identified patents and published application, many liquid jet-forming surgical instruments utilize liquid pressures in excess of 1,000 psig, often in the range of between about 5,000 to 20,000 psig, and in some cases up to 50,000 psig or more. Typical nozzle internal diameters can range from about 0.001 to 0.02 inch. In forming such instruments, the ability to fabricate liquid jet-forming nozzles able to withstand such pressures while forming collimated jets is difficult. Moreover, because, as mentioned above, many such instruments are disposable after a single use, the ability to form nozzles in expensively and reproducibly in quantity adds to the difficulty. Typical nozzle assemblies for forming collimated jets for liquid jet-forming devices can tend to be expensive to fabricate and/or difficult to fabricate in bulk quantities reproducibly and/or can have relatively large ratios of nozzle length to diameter, which can lead to undesirably large pressure drops. Many conventional methods for making such small nozzle openings, such as electric discharge machining, microdrilling, and the like, tend to be expensive, relatively slow, and difficult to automate. In addition, facilitating alignment between liquid jet nozzles and jet receivers in such instruments during fabrication, especially for instruments having relatively long jet lengths, e.g. greater than 5 mm can be difficult.
While many of the above-mentioned surgical instruments, and especially liquid jet-based surgical instruments have utility for performing such surgical and medical procedures, there for improved nozzles and nozzle assemblies for liquid jet-based surgical instruments and for improved techniques and components for aligning liquid jet-forming nozzles in such instruments. The present invention provides, in certain embodiments, such improved nozzles, nozzle assemblies, and surgical liquid jet instruments, and further provides methods for their construction and use in a variety of surgical procedures.